Additive Manufacturing (AM) is a process utilized to fabricate functional, complex objects without the use of molds or dies. Such processes include providing a material, such as a metal or plastic, in the form of a powder or a wire, and then using a powerful heat source (such as a laser beam, an electron beam, plasma welding arc, or the like) to melt and deposit a layer of that material on a substrate, such as a base plate of a work piece, or deposit the material on an existing object or part. Subsequent layers are then built up upon each preceding layer to form the complex object or part or work piece.
AM technologies may be thought of as a ‘tool-less’ and digital approach to manufacturing which provides companies and consumers with a wide and expanding range of technical, economic and social benefits. For example, AM technologies can be used anywhere in a product life cycle from pre-production prototypes to full scale production, as well as for tooling applications or post production repair and are stimulating innovation in component design to enable the manufacture of objects that cannot be made by traditional methods. The layer-wise nature of AM enables the manufacture of highly complex shapes with very few geometric limitations compared to traditional manufacturing processes. This freedom-of-design has led to the technology being used to manufacture topologically optimized shapes with improved strength to weight ratios for example, which is an important consideration in both the aerospace and automotive design fields to reduce vehicle weight and fuel consumption.
Selective Laser Sintering (SLS) is an example of an additive manufacturing technique. SLS utilizes a laser (for example, a carbon dioxide laser) to fuse small particles of plastic, metal, ceramic, or glass powders into a mass that has a desired three-dimensional shape. The laser selectively fuses powdered material by scanning cross-sections generated from a three-dimensional (3-D) digital description of the object (for example from a computer-aided design (CAD) file or scan data file) on the surface of a powder bed. After each cross-section is scanned, the powder bed is lowered by one layer thickness (which is typically very thin), a new layer of material is applied on top, and the process is repeated until the object is completed. With the advent of high-power lasers (in the range of 100's to 1000 Watts or higher), Direct Metal Laser Melting (DMLM) is typically utilized to completely melt metal particles during 3-D manufacturing of work pieces.
Finished object or part density depends on peak laser power, scan speed, beam size, beam focus, beam overlap and/or other aspects, but the key to getting high density parts is the energy density being delivered to the melt pool. As the melting point of metal powders is very high, a DMLM machine typically uses a high power laser that could be pulsed or continuous wave (CW). In some implementations, an electron beam metal powder bed machine (EB) DMLM preheats the bulk powder material in the powder bed to a temperature somewhat below its melting point, to make it easier for the laser to raise the temperature of the selected regions of the powder material the rest of the way to its melting point. Unlike some other additive manufacturing processes, such as stereolithography (SLA) and fused deposition modeling (FDM), DMLM does not necessarily require support structures because the object being constructed is surrounded by unsintered powder at all times, allowing for the construction of previously impossible geometries. However, some three-dimensional structures that include long overhangs or unsupported roofs require supports in order to print an accurate geometry and the desired surface finish. These support structures have two purposes. First, they offer physical support to an unsupported layer and keep it attached to neighboring structures, and second, the support structure gives a thermal pathway for the heat that is developed in the melt pool during the welding of an unsupported structure. With the powder acting as a thermal insulator in the DMLM process, it is necessary to try to control the thermal conductivity in the subsurface structure in order to keep the melt pool constant. When the melt pool overheats, it can become larger and affect both the feature resolution and surface finish of the object, especially on the downward facing unsupported surfaces. DMLM (as well as other AM techniques) is a relatively new technology that so far has mainly been used for rapid prototyping and for low-volume production of component parts. However, production roles are expanding as the commercialization of such AM technologies improves.
Therefore, it would be desirable to provide systems, apparatus and methods to help users, such as engineers and/or part or object designers, visualize the data collected from an AM process so that a better understanding can be obtained concerning the object being made, the effectiveness of the support structures being used, the consistency of the melt pool, and/or any potential object defects and/or the manufacturing process itself and/or the AM machine that is performing the manufacturing process.